The advent of the Internet has enabled online learning systems (also referred to as e-learning systems or tutoring systems), which implement educational technology in learning. In general, educational technology includes an array of tools, such as media, machines, and networking hardware, that enable users to access an online learning system as a pupil, and/or as an instructor. For example, a user can access the online learning system to learn about particular subjects (e.g., math, science). As another example, a user can access the online learning system to teach about a particular subject. For example, the user can submit content (e.g., text, images, video) that describes a solution to a math problem.